The Calibration kit is used for setting up PDC-2.6 HD, PDC-2.6P HD, HDP-3, HDP3-300 units. It includes the DEQX measurement, analysis and correction software for PC and USB cable as well as a DEQX Calibrated™ Behringer ECM3000 measurement microphone with cable.A boom microphone stand (not supplied) is required for speaker and room measurements. Stands are typically available for under $100 from a local musical instrument supply shop.For high-end speaker correction, the Reference calibration kit is recommended due to its high performance, higher bandwidth Earthworks microphone.  • 1 x Calibrated Behringer ECM3000 balanced measurement microphone • 1 x 7-meter Professional Assembled Microphone Cable • 1 x 5-meter USB Cable • CD containing DEQX™ Calibration Software (DEQX-Cal) for use on Windows PC or laptop • DEQX Users and Installers Manual Click here to download a specification sheet for the HDP-3 Preamp Processor.Specifications subject to change without notice.